Janet Rae-Dupree

Cheat Sheet / Updated 03-08-2022

To successfully study anatomy and physiology, you'll want to understand all the Latin and Greek roots, prefixes and suffixes. Also, make sure to get a good foundational knowledge of anatomic cavities, anatomic positions (standard positions when looking at an anatomical drawing), and anatomic planes.

Step by Step / Updated 06-29-2021

Atoms tend to arrange themselves in the most stable patterns possible, which means that they have a tendency to complete or fill their outermost electron orbits. They join with other atoms to do just that. The force that holds atoms together in collections known as molecules is referred to as a chemical bond. There are two main types and some secondary types of chemical bonds:

Article / Updated 03-26-2016

Science, especially medicine, is permeated with Latin and Greek terms. Latin names are used for every part of the body; and since the Greeks are the founders of modern medicine, Greek terms are common in medical terminology, as well. Latin and Greek roots This table represents some common Latin and Greek roots used in anatomy and physiology: English Form Meaning Example angi(o)– vessel angiogram arthr(o)– joint arthritis bronch– air passage bronchitis calc(i)– calcium calcify card(i)– heart cardiovascular cili– small hair cilia corp– body corpus luteum crani– skull cranium cut(an)– skin cutaneous gastr(o)– stomach, belly gastric gluc(o)– sweet, sugar glucosa hemat(o)– blood hematology hist(o)– webbing (tissue) histology hyster(o)– womb hysterectomy lig– to bind ligament osteo– bone osteoblast pleur– side, rib pleural cavity pulm(o)– lung pulmonary ren– kidney renal squam– scale, flat squamous thorac– chest thoracic vasc– vessel vascular Latin and Greek prefixes and suffixes This table represents some common Latin and Greek prefixes and suffixes you should know when studying anatomy and physiology: English Form Meaning Example a(n)– without, not anaerobic aut(o)– self autonomic dys– bad, disordered dysplasia ec–, ex(o)–, ect– out, outside exoskeleton end(o)– within, inside, inner endometrium epi– over, above epidermis hyper– excessive, high hyperextension hypo– deficient, below hypothalamus inter– between, among interoceptor intrañ within, inside intraocular iso– equal, same isotope meta– beside, after metacarpus ortho– straight, correct orthopedic para– beside, near, alongside parathyroid peri– around pericardium sub– under subcutaneous trans– across, beyond, through transplant –blast -to sprout, to make, to bud chloroblast –clast to break, broken osteoclast –crine -to release, to secrete endocrine

Article / Updated 03-26-2016

When you’re talking anatomy and physiology, the body is divided into sections, usually three planes. Separating the body into sections, or cuts, let’s you know which body half is being explained. The anatomic planes are: Frontal or coronal: Divides the body into front (anterior) and back (posterior) Sagittal or median: Divides the body lengthwise into right and left sections Transverse or horizontal: Divides the body horizontally into top and bottom sections

Article / Updated 03-26-2016

Your body’s cavities are basically the “holes” that would be left (besides bones and tissues forming the space) if you removed your internal organs. Your body has two main cavities; the dorsal and ventral. Ventral cavity: Extends from just under the chin to the pelvic area, encompassing the thoracic cavity, diaphragm, and abdomino-pelvic cavity Thoracic cavity: Contains the heart and lungs Abdomino-pelvic cavity: Contains the organs of the abdomen and pelvis Dorsal cavity: Contains posterior body organs extending from the cranial cavity into the vertebral canal housing the spinal cord Spinal cavity: Enfolds and protects the spinal cord Cranial cavity: Inside the skull and enclosing the human brain

Article / Updated 03-26-2016

Whenever you see an anatomical drawing, like the one below, you’re looking at the anatomic position. This standard position (standing straight, looking forward, arms at your side, and facing forward) keeps everyone on the same page when you’re talking anatomy and physiology. Keep this list handy of anatomic descriptive terms that appear regularly in anatomy text: Anterior: Front, or toward the front Posterior: Back, or toward the back Dorsal: Back, or toward the back (think of a whale’s dorsal fin) Ventral: Front, or toward the front (think of an air vent) Lateral: On the side, or toward the side Medial/median: Middle, or toward the middle Proximal: Nearer to the point of attachment (such as the armpit) Distal: Farther from the point of attachment Superior: Situated above, or higher than, another body part Inferior: Situated below, or lower than, another body part Peripheral: Away from the center

Article / Updated 03-26-2016

Assisted reproduction goes above and beyond people’s usual ideas about how humans make babies. Here is a glimpse into what humans have been doing to help Mother Nature perpetuate the species. Fertility medication: Used to treat female infertility, these drugs are used primarily to stimulate ovulation. The most widely used drug, clomiphene (known in the U.S. by the brand name Clomid), inhibits estrogen receptors in the hypothalamus, which results in the pituitary releasing more of the hormones required for ovulation. Doctors also sometimes prescribe drugs to stimulate the hypothalamus to release hormones called gonadotropins, or they introduce gonadotropins directly, either from natural sources or created artificially. Some studies indicate that Clomid taken in combination with Vitamin E can partially reverse oligospermia, or male infertility. Intrauterine insemination (IUI): More popularly known as artificial insemination, this procedure uses a long, narrow tube to place sperm directly into the uterus. It’s used for myriad reasons, including when women have scarring or defects of the cervix, or when low sperm count or motility makes natural insemination unlikely to lead to pregnancy. In vitro fertilization (IVF): This means simply that fertilization occurs outside of the body. Known as the most effective assisted reproductive technology, or ART, this procedure long has borne the misnomer of “test tube babies.” Rather than a test tube, fertilization takes place in a flat Petri dish. IVF begins with fertility drugs to stimulate the ovaries to produce multiple eggs. When the eggs mature, they are “harvested” from the ovaries and mixed with sperm. After three to five days, one or more of the resulting blastocysts are transferred into the uterus. Zygote intrafallopian transfer (ZIFT): Also known as tubal embryo transfer, this procedure is similar to IVF, but the zygote is transferred earlier and into the Fallopian tube instead of the uterus. Gamete intrafallopian transfer (GIFT): Eggs and sperm are collected artificially, as in IVF, but in this case the harvested eggs and sperm are placed together into the Fallopian tube instead of a Petri dish, so that fertilization takes place inside the body. Intracytoplasmic sperm injection (ICSI): The usual steps of IVF are followed, and the eggs are harvested, but rather than being mixed in a Petri dish, a single sperm is injected into each mature egg before the blastocysts are transferred either into the uterus or the Fallopian tube. This option can be used when there is a very low sperm count, when there are problems with motility, or if the sperm must be collected directly from the testicles or epididymis. In addition to technical interventions, assisted reproduction also can involve the use of eggs donated from another woman, donated sperm, or frozen embryos created during a couple’s earlier IVF cycles or donated from an unrelated couple. These options sometimes are chosen if a couple carries a genetic disease that could be passed on to a baby, if a woman has older eggs, or if she cannot ovulate.

Article / Updated 03-26-2016

From almost the moment they were discovered, bacteria have had a rotten reputation. “Germs,” people called them. “Bugs.” People scrubbed them away, developed drugs to kill them, cursed them for causing sickness and death. It turns out, however, that the 100 trillion microbes living in and on people — that’s ten single-cell organisms for every one human cell — are a fundamental component of human physiology. In a very real sense, the human microbiome is as much a functioning organ as are the intestines into which so many of them are packed. But their influence goes way beyond the digestive tract, into such sites as the skin, eyes, urogenital tract, nose, and lungs. Researchers studying this cloud of microbes have called them the “second genome.” A person’s microbiome starts to grow at birth — in fact, it may gain a toehold even before a person is born — and ultimately develops into a collection of on-board ecological systems somewhat akin to coral, with distinct colonies living in symbiosis. Even though bacteria are one-tenth to one-hundredth the size of a human cell, every person carries around up to five pounds of them. In other words, the microbes a person hosts weigh more than the three-pound brain does. Until the advent of the Human Microbiome Project, which launched in 2007, very little was known about these stowaways. There was evolving understanding that many of them are essential to human life, that they help to synthesize certain nutrients, form a defense network against harmful microbes, and play an important role in digesting food. But they were tough to study. Many simply couldn’t be grown outside the body, and even those that could be cultured in the lab failed to behave the way researchers thought they might in vivo, or inside the body. Gene sequencing technology developed during the race to map the human genome, however, has created a new field of research called metagenomics that lets researchers study microbial communities without having to culture them in the lab. New discoveries are being published regularly, including the following: There are more than 10,000 microbial species within the human ecosystem — several times more than previously thought — and every human is host to a unique collection of more than 1,000 species. Every human hosts one of only three distinct ecosystems of gut microbes, which in the future may allow microbiome “typing” similar to what has been done since the identification of blood types. While the human genome includes roughly 22,000 genes that code for proteins, the microbiome has more than 8 million unique protein-coding genes, which means there are 360 times more active bacterial genes than human genes in the body. The microbiome provides crucial components for digesting and absorbing nutrients, but different species play the same role in different people. Even healthy adults play host to pathogenic microbes known to cause illness, but these pathogens simply coexist harmlessly in the microbiome. Researchers in 2014 published an expanded catalog of nearly 9.8 million genes from the human gut microbiome that is three times larger than any previous list of genes.

Article / Updated 03-26-2016

Think people know everything there is to know about human anatomy? Think again. Researchers announced the discovery of two new body parts in 2013 alone. The first new anatomical feature was announced in June, when a previously unknown layer was discovered in the eye’s cornea. Now called Dua’s Layer after Prof. Harminder Dua, who led the study at the University of Nottingham in England, the newly identified section lies between the corneal stroma and Descemet’s membrane. It is strong, impervious to air, and only 15 microns thick, roughly one and a half times the length of a human red blood cell. Prior to the discovery, the cornea was believed to have only five layers (from the outside in): the corneal epithelium, Bowman’s layer, the corneal stroma, Descemet’s membrane, and the corneal endothelium. Now that Dua’s layer has been identified, however, doctors are beginning to understand that a malformation or damage to this layer can be related to disorders at the back of the cornea. Eye surgeons also are taking advantage of Dua’s layer by injecting air bubbles needed during some surgeries under the layer rather than above it, where there is a chance of air causing damage to the corneal stroma. The second addition to clinical anatomy textbooks was announced in November, when surgeons at the University Hospitals Leuven in Belgium fully described a knee ligament about which clinicians had been hypothesizing since 1879. Two Belgian surgeons had become frustrated that some of their patients who had undergone repairs to their anterior cruciate ligament, or ACL, still experienced trouble with the knee giving way mid-motion even after the surgical recovery appeared to be complete. After doing detailed dissections of 41 knees from cadavers, Dr. Steven Claes and Prof. Dr. Johan Bellemans found that all but one of the knees had a previously unidentified feature, now known as the anterolateral ligament, or ALL. Subsequent studies showed that surgical patients whose knees remained unstable, a condition known as “pivot shift,” still had damage in the ALL. As a result, researchers now believe that the ALL controls the rotation of the tibia (the “shinbone”) inside the knee joint. The Belgian surgeons now are working on new techniques to correct those injuries. Tears in the ACL are common among athletes in sports that place demands on the knees for rapid shifts and changes in direction, such as skiing, soccer, rugby, and basketball. Why are researchers still discovering new things about the anatomical structures of the human body? Because the body is an intricate thing, with sometimes extraordinary variation from one individual to another. One example: An arm muscle known as the palmaris longus simply isn’t there in up to 15 percent of the population. To complicate things further, some people have the muscle in one of their arms, but not the other. And that’s not the only elusive part; the plantaris muscle of the leg is missing from 1 in 10 people, and the levator claviculae in the neck is so rare — only 3 in 100 people have one — that it’s considered to be a vestigial muscle. Keep in mind, too, that researchers are still delving into the microscopic details of how the brain and the nervous system are put together. In other words, stay tuned for further anatomical updates!

Article / Updated 03-26-2016

All matter — be it solid, liquid, or gas — is composed of atoms. An atom is the smallest unit of matter capable of retaining the identity of an element during a chemical reaction. An element is a substance that can’t be broken down into simpler substances by normal chemical reactions. There are 98 naturally occurring elements in nature and 20 (at last count) artificially created elements for a total of 118 known elements. However, additional spaces have yet to be filled in on the periodic chart of elements, which organizes all the elements by name, symbol, atomic weight, and atomic number. The key elements of interest to students of anatomy and physiology are Hydrogen: Symbol H Oxygen: Symbol O Nitrogen: Symbol N Carbon: Symbol C HONC your horn for the four organic elements. These four elements make up 96 percent of all living material. Atoms are made up of the subatomic particles protons and neutrons, which are in the atom’s nucleus, and clouds of electrons orbiting the nucleus. The atomic weight, or mass, of an atom is the total number of protons and neutrons in its nucleus. The atomic number of an atom is its number of protons; conveniently, atoms that are electrically neutral have the same number of positive charges as negative charges. Opposite charges attract, so negatively charged electrons are attracted to positively charged protons. The attraction holds electrons in orbits outside the nucleus. The more protons there are in the nucleus, the stronger the atom’s positive charge is and the more electrons it can attract. Simplified models assume that electron particles orbit the nucleus at different energy levels, known as shells. But quantum theory best describes information about electron-states using wave functions, or orbitals. Each orbital has a four-quantum-number address (characteristic energy, 3-D shape, orientation, and spin). The principal quantum number is the shell. The other numbers allow room to add distinct electrons. Shells are divided into subshells, and these are filled to completion in order of increasing energy. The first shell holds only two electrons, of opposite spin (magnetism). The second and third shells each hold eight electrons in four subshells and two spins. The fourth shell (which can be found in elements such as potassium, calcium, and iron) holds up to 18 electrons. Higher shells also exist. Other key chemistry terms that you need to know are Isotopes: Atoms of an element that have a different number of neutrons and a different atomic weight than usual. In other words, isotopes are alternate forms of the same chemical element, so they always have the same number of protons as that element but a different number of neutrons. Ions: Because electrons are relatively far from the atomic nucleus, they are most susceptible to external fields. Atoms that have gained or lost electrons are transformed into ions. Getting an extra electron turns an atom into a negatively charged ion, or anion, whereas losing an electron creates a positively charged ion, or cation. To keep anions and cations straight, think like a compulsive dieter: Gaining is negative, and losing is positive. Acid: A substance that becomes ionized when placed in solution, producing positively charged hydrogen ions, H+. An acid is considered a proton donor. (Remember, atoms always have the same number of electrons as protons. Ions are produced when an atom gains or loses electrons.) Stronger acids separate into larger numbers of H+ ions in solution. Base: A substance that becomes ionized when placed in solution, producing negatively charged hydroxide ions, OH–. Bases are referred to as being more alkaline than acids and are known as proton acceptors. Stronger bases separate into larger numbers of OH– ions in solution. pH (potential of hydrogen): A mathematical measure on a scale of 0 to 14 of the acidity or alkalinity of a substance. A solution is considered neutral, neither acid nor base, if its pH is exactly 7. (Pure water has a pH of 7.) A substance is basic if its pH is greater than 7 and acidic if its pH is less than 7. The strength of an acid or base is quantified by its absolute difference from that neutral number of 7. This number is large for a strong base and small for a weak base. Interestingly, skin is considered acidic because it has a pH around 5. Blood, on the other hand, is basic with a pH around 7.4.